But a review, ordered by the London mayor, said the estimated costs of the project are escalating from an initial £60 million to more than £200 million.

Dame Margaret Hodge, the Labour MP who wrote the report, also said the purpose of the bridge remains unclear and the procurement process in which Heatherwick Studio won the contract to build it was ‘not open, fair or competitive’.

In a letter to Dame Margaret, Khan thanked her for the ‘thorough report’, adding: ‘I have been clear since I became Mayor that I will not spend a penny more of taxpayers’ funds, for which I am responsible, on the Garden Bridge. That remains the case.’

Sadiq Khan said he will thoroughly look at the report’s findings (Picture: REX/Shutterstock)

Dame Margaret was asked to conduct the review in October last year, but her findings have only now been released to the public.

She wrote: ‘The project has already used £37.4 million of public money and the agreed underwriting by the Government of costs could bring the bill to the taxpayer up to £46.4 million if the project is cancelled.